From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.science.mathematics.categories/5878 Path: news.gmane.org!not-for-mail From: "Eduardo J. Dubuc" Newsgroups: gmane.science.mathematics.categories Subject: isomorphisms Date: Sat, 29 May 2010 18:18:28 -0300 Message-ID: Reply-To: "Eduardo J. Dubuc" NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: dough.gmane.org 1275231462 3345 80.91.229.12 (30 May 2010 14:57:42 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sun, 30 May 2010 14:57:42 +0000 (UTC) To: Categories list Original-X-From: categories@mta.ca Sun May 30 16:57:40 2010 connect(): No such file or directory Return-path: Envelope-to: gsmc-categories@m.gmane.org Original-Received: from mailserv.mta.ca ([138.73.1.1]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1OIjxI-0006AF-8i for gsmc-categories@m.gmane.org; Sun, 30 May 2010 16:57:36 +0200 Original-Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1OIjRj-0006J0-RS for categories-list@mta.ca; Sun, 30 May 2010 11:24:59 -0300 Original-Sender: categories@mta.ca Precedence: bulk Xref: news.gmane.org gmane.science.mathematics.categories:5878 Archived-At: isomorphims appear not only in examples but are essential also in the theory. For example Grothendieck defines limits and colimits of categories (as universal pseudocones) in SGA4 by means of an isomorphism of categories. Same for toposes. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]